Are you by any chance trying to do
windows\adb push rectools.tar.gz /sdcard/
in FASTBOOT mode? I tried that and indeed, adb didn't see the device. However, the correct command to run in FASTBOOT mode is:
windows\fastboot flash recovery recovery.img
And that one worked.
PS: when you mention "I followed these instructions to the letter", have you also looked at the Galaxy wiki? Unfortunately I installed all the drivers a month ago and didn't document the process faithfully at the time. Your insight would be helpful.
The Samsung Galaxy wiki is my attempt to centralize information about the Samsung I7500 Galaxy.

Summary of changes to Paul's first post (I messaged him, hopefully he'll edit the post):
1. The / after 'windows' should be \
2. The windows/adb mount /sdcard command is not necessary (and won't work)
3. You must install New PC Studio and all the USB drivers, then you must enable USB debugging for adb to detect your device.
If adb returns an "error: device not found", please see How to fix adb error: device not found on the Samsung Galaxy wiki.

I wouldn't have my SMSes migrated somewhere online, for privacy reasons.
PIM Organizer is a piece of freeware that exports SMSes to text files. It probably can import them too, but I haven't tried that. Exporting worked perfectly and I periodically export my SMS Inbox and move the files out of the PDA to my computer.